1. Field of the Invention
This invention relates to a driving control device and method for power converting system specialized in automatically calculating the slope parameter for inductor current and providing this parameter to the power converting system for driving the control.
2. Description of the Prior Art
The conventional digital-controlled switching power converting circuit is better than the analog-controlled ones because the circuit aged slower, less power consumption, easier to modify the algorithms, and easier to design and accomplish. But the quick analog/digital convertor senses and feedbacks current and voltage to the digital controller, sampling frequency will affect the result. It needs to raise the sampling frequency to observe more data to solve this problem and minimize the error.
Raising the sampling frequency causes more converting time and as part of the feedback loop, it also causes extra phase lag. Besides the phase lag in analog control, the delay of converting process will result in extra waiting loop and slow down the instant reaction. High sampling frequency analog/digital convertor is also more expensive.
So as to avoid the delay of converting and save cost on components, it is necessary to lower sampling frequency. Under the condition of low sampling frequency, a practical way is to use inductance to calculate the slope parameter for inductor current of switching power converting circuit while controlling current, and use it to control the duty cycle of pulse signals.
As shown in FIG. 1 is an oscillogram of current used technology. With the known slope parameter for inductor current m1 and m2, the duty cycle of pulse signal can be determined by referring to the difference between the referring current Iref and sampling inductor current iL,1, and the slope parameter for inductor current (use sampling period T[n] to sample inductor current iL and calculate the width of the pulse control signal D[n]·T[n]). Since the actual inductance is hard to obtained and measured, high-accuracy current control cannot be achieved because there is no accurate slope parameter for inductor current.
So as to know, the current known practice has lot of drawbacks, is not a good design, and must be improved.
Noticing the disadvantages of the current method mentioned the inventor of this invention dedicates to improvement and invention. After years of hard working, this invention of automatically measuring the inductor current slope parameter for driving control device and method for power converting system is successfully invented.